The invention discloses an information terminal and a control method thereof. Even if the information terminal is taken away by the third party, improper usage of the information terminal can be prevented. The information terminal includes a detection part and an invalidation part, wherein the detection part detects the receiving signal intensity of a wireless signal received from a fixed device through a wireless part; and the invalidation part enables input of an input device to be invalid when the receiving signal intensity detected by the detection part is less than the specified threshold value.